Attrition mill



Sept- 26, 1961 F. c. VAUGHAN ETAL 3,01731 ATIRITION MILL Filed Oct. v29. 1953 2 Sheets-Sheet 1 INV EN TORS MYJM F27 roe/v; Y

between the discs.

of the shaft.

3,001,731 A'I'I'RITION MILL Frank C. Vaughan, Richmond, Va., and Maurice D.

' ,Woodruif, Springfield, Ohio, assignors to The Bauer Company, Springfield, Ohio, a corporation of Filed ocr. 29, 1953, ser. No. 389,054 s claims. (C1. 241-256) VThis invention relates to mills and more particularly to mllls of thev disc type for the abrading and rening of pulp and other type of iibrous materials.

'The object of the invention is to improve the construc- .tion as well as the means and mode of operation of disc mills whereby they may not only be economically manufactured, but will be more eicient in use, semi-automatic m operation, uniform in action, having a minimum number of working parts yet provide for easy access, and be 'unlikely to get out of repair.

The object of the invention is to achieve a reorganization of mill structure, with the View of providing'better balance, easier and more accessible means of adjustment and a more reliable and trouble free operation.

More speciiically, it is an object of the invention to provide a simple and eiective means of gaining access to the refining chamber wherein the material is reduced or ground between opposing discs.

Another object of the invention is to improve the .bal-

ance and operational characteristics of the mill by mounting the rotating disc between spaced apart bearings.4

A further object of the invention is to provide for variation in clearance between the dis through adjustment of the main driving shaft.

- Still another object of the invention is to utilize hy- `draulic means in the adjusting of the shaft and as a lshock absorber in the presence of unrenable material A still further object of the invention is to make a dual use of a thrust bearing on the shaft whereby it may serve also as a piston in the described hydraulic movements -in Yvi'ew as will more fully appearin the specification,

the invention intended to be protected by Letters Patent consists of the features of construction, the parts and combinations thereof, and the mode of operation, as hereinafter described or illustrated in the accompanying drawings, or their equivalents.

In the accompanying drawings, wherein is shown one -but notl necessarily the only form of embodiment of the invention, Y lFIG. 1 is a view in longitudinal section ofa disc mill vin accordance with the illustrated embodiment of -the invention; Y

FIG. 2 is an end view of the mill of FiG. l, showing the stationary disc in an operating position; FIG. 3 is a fragmentary View similar to FIG. 2, show- 'ing the stationary disc rocked a distance of aboutV ninety degrees from the position of FIG. 2; and

FIGS. 4 and 5 are views in cross section taken substantially along the respective lines 4--4 and 5-5 of vFIG. 1.

Like parts are indicated by similar characters of reference throughout the several views. Referring to the drawings, Va disc mill in accordance aired States Patent C 5.1@

Patented Sept.A 26, ,1961

with the illustrated embodiment of the invention comnprises ra base 10 from which rises a support housing 11.

The latter provides spaced bearing supports 12, and a'r'r intermediate relatively large refining area receiving grinding discs 13 and 14. The discs 13 and 14 are arranged in coaxial adjacent relation and have detachable face plates 1S and 16 which coact to reduce material introduced therebetween. A supplemental housing 17 surrounds the discs 13 and 14 Vforming therein a closed chamber 18. The material is applied to the discs 13 and 14, at the center thereof, by an inlet tube 19, and, in response to relative rotation of the discs 13 and 14 the material passes radially outward between the plates 15 and 16, discharging into the chamber 18 and owing out of the mill by way of a communicating outlet tube 21.

The disc 14 is a fabricated element, made water-tight for purposes of better balance. It is secured to shaft 23 which is disposed in parallel relation to the base 10 coaxially of the discs 13 and 14. The shaft 23 extends axially through the discs 13 and 14 and is supported in bearings on opposite sides of the disc assembly for purposes of balance and better distribution of bearing load. One bearing for the shaft 23 is contained in a housing 24 installed in the support 11 and comprises a grooved sleeve 25 on the shaft, a relatively elongated race 26 on the interior of the housing *24, and interposed roller bearings 27. One end of the shaft 23 extends through and beyond the bearing housing 24 and is adapted. for operative engagement with a suitable rotary driving mechanism. 1

The opposite end of the shaft 23 is received in a sleeve 28 which has a rotatable bearing in a concave surface 29 of the support 11. A bearing housing 31 has a press t in the sleeve 28 and provides the other bearing'for the shaft 23, such `bearing including an elongated race 33, and bearings 34`located in a grooved sleeve'35 fastened to the shaft.

rDhe'sleeve 28 is integrally united, through an adapter super structure 36, with the disc i13. An overlying clamp member 37 is arranged in complementary relation to the concave surface Z9 yalternatively to grip and hold the sleeve 28 against rotation or to release the sleeve for rotation. Such adjustments [are accomplished by tightening or loos.- ening bolts 38 (FIG. 4) which are normally tightened so that the sleeve 28 audits associated parts, including the disc 13, are relatively stationary.

in response to rot-ation of the shaft 23, the disc 14 rotates relatively to the disc 13 to effect the rening or reduction of the material supplied by way of inlet 19, The material entering by way of inlet 19 constrained to follow a path cent-rally of the discs 13 and 14, and radially outward between the plates 15 and 16 thereon, by an arrangement of baiies 39 and 41 and by a seal 42 which inhibits iiow of the material along the shaft'23 into the sleeve 28.

The aforementioned auxiliary housing 17 is in part deiined by a ring 43 in surrounding spaced relation to the discs 13 and 14 and resting at its one end on the housing 17 proper. The opposite end of the ring 43 is operatively engaged with an annulus 44 extending from and forming a part of the adapter 36. A circumferential series of attachment means are provided on the ring 43 and the annulus 44, such means including brackets 45 on the ring 43, brackets 46 on the annulus 44 and interconnecting tie members 47. The ring 43 normally occupies a position overlying the space between the annulus 44 and the hous.- ing 17 proper. The chamber 18 accordingly is closed and the ring 43 may be considered to be in a closed position. Upon release of the connection alorded by the tie members 47 the ring 43 may be slid vaxially to a position as indicated in dotted lines in FIG. l. This may be considered its open position since the chamber -18 is open and the discs 13 and 14 `are accessible for cleaning or servicing.

Due to the size and weight of the machine, and particularly the plates 15--16 there is presented Va problem ofaccess and convenience in the servicing and Vmaintenance of the present machine. Problems 'of substantially th'e'same magnitude are presented in mills presently being ligoonnat .l

used Yand heretofore there has been no solution offered.V

'In .the present disclosure the vso-called Xed or nonrotating plate V13 'and its associated face pieces 15 are so mounted through the medium of the tubular sleeve 23 that .they-may be rotated through a limited range to improve vthe 'servicing and maintenance' problem. vAfter release of the connections 45-47 and movement ofthe 'ring 43 'toits open position, 'the `adjustment bolts 3S are loosened. The tubular sleeve 28 is thereby released for rotary motion relative tothe support 11 and the enclosing cover or .clamp member 37. The plate or disc 13 4 ment of the plates 1S and "16 and by turning a wheel 63, post 61 is advanced into engagement with the plate 53. This provides a zero setting of the plates 15-16 and a reference point from which other settings of plate clearances are made. To set the plates 15-16 to desired clearance, pressure uid is admitted to the chamber 56 on the left side thereof, ie., intermediate plates SiS-58, to thereby move 23 and associated plate 14 "toward :therighL Thereupon lthe post .61 is advanced the amount of the desired clearance and locked by appropriate `rotation of the lock nut 64. Pressure'fluid .is then admitted to the right side of chamber 56 andthe bearing assembly 49 ,Y caused to travel to theY left until it is stopped by plate 53 and its associated elements may then be manually rotated a distance of approximately 90 in either direction from its normal position 'as shown in FIG. 2. FIG. 3 shows the plate '13 and associated elements rotated in one udirection from martinmV Thus the face plate 15 which normally comprises individual sectors secured to the vplate lf3 may be easily removed a sector at artime for repair 'or replacement. The uppermost :sectors are removed whilethe plate '13 is'in normal position, vafter which the plate 13 is rotated in rst one direction and then the other toflbring the 'lowermost sectors of vface plate 15 Ainto the upper Ahalf ofthe housing for Veasy removal.

The left hand or inner end of the shaft 23 terminates Within thesleeve 2S and has a collar 4S secured thereto by means including a lnut 50. The 'collar 4S.is apart 0f a thrust bearing assembly 49 which further includes n -surrounding sleeve 51, Vtwo sets of shoe elements 52 rand lend plates 53 'and 54. The bearing 49 is a commercially available unit known 'as Ia Kingsbury bearing and functions 'to absorb "endwise thrust upon the shaft 23 without material interference with rotation of the shaft. The sleeve 51 is connected, as by a vkey 55, with the sleeve 28 and further is grooved to separate the shoes 52 from 'one 1another and to prevent theirrrot'ation with the col- The vbearing 49 is disposed in a chamber 56 closed at its one end by 'a disc 57 abutting 'the bearing bushing 31 'closed at its other end by a plate 58 held in place on'the end'of the sleeve 28 by a lclosure cap 59. A screw post 61 has -a-scrcw'threa'ded mounting in the cap 59 and Yextends' through the plate 58 into the chamber 56 to dene aplimit oflongitudinal motion for vthe bearing 49 in one direction. A non-rotating sleeve 62 is secured to plate 54 and forms a 'sliding seal with plate 57 and 'with the sleeve '2'8 Yand plates 54 and 57 definesy the right 4hand' end of chamberd 'Y The chamber 56 functions yas a hydraulic pressure chamber, Wth'fthe bearing 49 serving as a piston therein ifor the purpose of moving the shaft 23 in an endwise or axialdirection to eect a relative approaching or withdrawing motion of the discs 13 yand 14. Such motion or" Y the shaftY is permitted by the aforementioned elongated races 26 and 33 in the bearing housing 24 and V31. The v'chambend on opposite sides of the bearing 49 is connectedin amanner not here shown ina hydraulic circuit.

Injdening the vinitial position 'of adjustment of the discs 13 and 14, the lscrew post 61 is retracted out of an operational position. The hydraulic circuit then is adjusted Vto admit Vpressure uid through passages 65 vto the chamber Y56 on the rightllran'd Vside `of the bearing 49 and atov'connect the opposite orleft-hand end of the chamber through passage 67 to asupply tank (not shown). As a result, the piston bearing 49 and the shaft 23 move leftward to eiectan approaching motion of the disc 14 toward the disc 13. This motion continues until the iplate16'contacts the plate 15 which will make a sound rordinarily audible tothe operator. l'l'he leftward motion fozfgthe'shaftll 'and `associated parts'is halted by engagecontacting .post 61, to maintain the minimum Clearance between plates 15-16. Y

Hydraulic force in the rright hand end of the chamber 56 holds the piston'bearing 49 to a seat on the post .61 and such force is made resilient by means of a pressure reservoir (not shown) so that if pieces of metal .or other vsolid particles are inadvertently Yfed between the plates 15.and 16 the disc V14 can `yield 'by moving to the right a distance required to pass the `foreign material from between the discs.

For this purpose .the passages 65 extending from the right hand e'nd of the chamber 56 through the plate v57 and the lbearing 'bushing v3l also communicate with a .pressure fluid reservoir, not shown. From the left hand end of chamber 5.6, the pipe 67 communicates .through a metered check valve 66 with the tank (not shown). The check valve 66 is arranged so that duid leaving the left hand end of chamber 56 is restricted .in iiow by an orifice through the .check but llow .into the .chamber is unrestricted. If .during operation of the machine an axial Vimpulse in aright hand .direction is imparted -to Ythe shaft 23, the pressure in the right hand end of chamber 5.6 rises above the normal value. This vresultsrin passage ofsome of .the'hydraulicuid out ofthe chamber 5 6 by way of passages 65, allowing vthe ,piston bearing@ to `move .ina right .hand direction a distance 'measured lby the volume of displaced iluid. During this movement, fluid enters the left hand end of chamber 56 -through passage 67 .and check valve 66. When the applied .axial thrust .is released, thepiston bearing is returned by .hydraulic pressure continuously supplied the chamber 56 at its .right hand end, to aposition of abutment with the screw post 61. The specd'of travel of the piston bearing is limited by the escape of hydraulic huid from the left end of .chamber 56 through the orice in check -valve 66 and thereby avoidsdamage to the machine when the piston bearing contacts the screw post 61.

From the above description Ait vwill be apparent that there iis'thus provided a device of the characterdescribed possessing 'the vparticular features of advantage before enumerated as desirable, but which obviously Ais susceptible of v:modiiication 4finits form, proportions, detail iconstruction and arrangement of Vparts without departing from the principle vinvolved or sacricing any `of fits .ad-l vantages.

While in order to comply with the statute the invention has been described in language more or less 'specic as to structural features, it is to be understood that the invention is not limited to the specific 'features shown, but that the means and construction herein disclosed comprise but one of several modes of putting the invention into effect.

Having thus described our invention, we claim:

l. A ydisc mill, including a relatively 'stationary housing, a pair of grinding discs in adjacent parallel relation, a shaft extending longitudinally through rsaid grinding discs, and projecting at its opposite ends beyond'said discs, one of said discs being secured to said shaft, va radial'bearin'g in said housing lfor one projecting end of said shaft, la tubular sleeve extending from the other one of said discs in surrounding spaced relationto the other :projecting f end lof 'said ,fshaft and 'supported "in said housing, -a radial bearing in said tubular sleeve for the other projecting end of said shaft, said tubular sleeve being supported in said housing for relative rotary motion, and means for releasably holding said tubular sleeve in selected positions of rotary adjustment.

2. A disc mill, including a base, a pair of coaxial grinding discs supported thereon, one a rotating disc and the other a relatively stationary disc, an enclosure for said discs including an annular ring arranged for longitudinal sliding movement relative to said enclosure, said ring being slidable to an open position providing access to said discs, a rotatably adjustable mounting for said stationary disc whereby successive portions of said disc may be brought to a position of access, and means for maintaining said annular ring in closed position relative to said enclosure.

3. A disc mill, including a stationary housing, a pair of coaxial grinding discs, a rotatable shaft extending through said discs and having its opposite ends projecting on opposite sides thereof, one of said discs being secured to said shaft, a radial bearing in said housing for the projecting end of said shaft adjacent to said last named disc, a tubular superstructure secured to the other one of said discs and extending in surrounding spaced relation to the other projecting end of said shaft to a rotary mounting in said housing, a radial bearing for the other projecting end of said shaft in said superstructure, and means for holding said superstructure against rotation relatively to said housing.

4. A disc mill according to claim 3, characterized by an annular access door surrounding said discs and detachably `anchored to said tubular superstructure at a plurality of circumferential points thereon, the said means for holding said superstructure against rotation being releasable for rotation of said tubular superstructure and associated disc to bring successive portions of said disc to a position of access.

5. A disc mill, including a stationary base, longitudinally spaced apart bearing supports rising from said base and defining therebetween a rening area, the upper ends of said supports having concave bearing surfaces, a pair of relatively rotatable grinding discs in said area, an open ended sleeve received in the bearing surface on one of said supports and united at its one end with the rear of one of said grinding discs, a radial bearing in the concave bearing surface on the other one of said supports, another radial bearing in said sleeve, and a shaft extending axially through said grinding `discs and connected to the other one of said discs for unison rotation, the opposite ends of said shaft being received in said radial bearings and rotatably supported therein, the radial bearing in said sleeve spacing said sleeve from said shaft, one end of said shaft extending through and beyond the radial bearing in said sleeve, a piston on said one end of said shaft, the opposite end of said sleeve being closed and the space beyond said piston being filled with a hydraulic iluid whereby to provide in said sleeve a thrust bearing for said shaft.

6. A disc mill according to claim 5, characterized in that the other end of said shaft extends through and beyond the radial bearing in the said other one of said supports, said other end of the shaft being adapted for connection with power rotating means `for said shaft.

7. A disc mill, including a stationary base, longitudinally spaced yapart bearing supports rising from said base and deiining therebetween a rening area, a pair of relatively rotatable grinding discs in said area, a sleeve received in one of said supports and united at its one end with the rear of one of said grinding discs, a radial bearing in said sleeve and another radial bearing in the other one of said supports, a shaft extending between and supported in said bearings, `said shaft passing through said discs and being connected to the other one thereof for unison rotation, a housing enclosing said discs including a housing component secured to the said other one of said supports and a ring resting on its one end on said housing component and detaohably connected at its other end to the assembly comprising said sleeve and said one disc said ring when detached from said assembly being slidable on said housing component to expose said discs for access thereto.

8. A disc mill according to claim 7, characterized by means for releasably holding the assembly comprising said sleeve and said one disc against rotation in said one support, lsaid assembly being rotatable when said ring is `detached from said sleeve for access to all parts of said one disc.

References Cited in the ftle of this patent UNITED STATES PATENTS 421,063 Althouse Feb. 11, 1890 614,316 Baker Nov. 15, 1898 1,135,313 Moore Apr. 13, 1915 1,206,316 Ellis Nov. 28, 1916 1,520,237 Gilchrist Dec. 23, 1924 1,970,330 Mason Aug. 14, 1934 2,113,040 Anderson Apr. 5, 1938 2,156,320 Sutherland May 2, 1939 2,338,198 Pall Jan. 4, 1944 2,654,541 Sullivan Oct. 6, 1953 

